In general, airbag systems are devices to protect an occupant in a vehicle by absorbing physical impact caused upon vehicle collision using the elasticity of an airbag cushion. The airbag systems may be classified into a driver airbag system, a passenger airbag system, and a side airbag system.
The side airbag system is generally installed at a seat or a pillar of a vehicle to prevent the head and the shoulder of an occupant from colliding with the door, prevent the occupant from being injured by fragments of a broken door window, or prevent the occupant from being sprung out of a vehicle body when the occupant is inclined to the door or the door is dented inward upon the side collision of the vehicle.
Hereinafter, a side airbag cushion according to the related art will be described with reference to FIG. 1.
An airbag cushion 10 employed in an airbag system according to the related art may be partitioned into a lower chamber 40 to protect the hip of an occupant and an upper chamber 50 to protect the chest and the shoulder of the occupant. The lower chamber 40 is distinguished from the upper chamber 50 by an internal baffle 30, and the internal baffle 30 is provided therein with a through hole (in the shape of a semicircle in FIG. 1) used to supply gas from the lower chamber 40 to the upper chamber 50. In addition, the upper chamber 50 is provided therein with a vent hole 20 to exhaust gas to the outside after a predetermined gas pressure has been made in the upper and lower chambers 50 and 40.
In the above structure, gas is primarily introduced into the lower chamber 40 by the explosion of an inflator (not shown) to inflate the lower chamber 40, and introduced into the upper chamber 50 via the through hole to inflate the upper chamber 50.
However, according to the related art, in the state that the internal space of the upper chamber 50 communicates with the internal space of the lower chamber 40 by the through hole formed in the baffle 30, if the upper and lower chambers 50 and 40 are inflated beyond a predetermined extent, the gas is exhausted to the outside through the vent hole 20. Accordingly, the deployment volume of the upper and lower chambers 50 and 40 is gradually reduced.
Meanwhile, the shoulder of the occupant may be less injured than the chest of the occupant in the body structure of a person. Accordingly, researches and development are required for the structure of an airbag cushion capable of more minimizing the injury degree of the occupant by moving a portion of the load (impact) applied to the weaker chest of the occupant to the shoulder of the occupant.
However, according to the airbag cushion 10 of the related art, since the upper chamber 50 that may make contact with the shoulder of the occupant has no structure to especially push the shoulder of the occupant toward the interior of the vehicle, the above load distribution may not occur. In this case, since the load applied to the chest of the occupant is not properly distributed upon vehicle collision, the rib of the occupant may be injured.